It has heretofore been required that, when two or more numbers of printed circuit wiring boards are stacked one on another, a space interval be maintained between the adjacent printed circuit wiring boards with spacers, each being in a columnar shape, interposed between these neighboring printed circuit wiring boards and fixed with threaded bolts so as to fasten them together mechanically.
However, with an electronic device becoming smaller and smaller in size, the printed circuit wiring boards used for it are also required to be small in size and be stacked in a multi-layered structure. As a consequence of this, it has become difficult to leave a space on the printed circuit wiring boards for fitting the spacers.